Analytical methods for determination of trans fatty acid content in food

Juanéda, Pierre; Ledoux, Martial; Sébédio, Jean‐Louis

doi:10.1002/ejlt.200600277

Cited by 41 publications

(33 citation statements)

References 80 publications

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“…None were assayed in a collaborative study format for complex food and milk fat products. This is true not only for trans CLA, but also for determining compliance with nutritional labelling provisions for many minor trans fatty acids in complex foods [80].…”

Section: Discussionmentioning

confidence: 99%

Trans fatty acids: Definition and occurrence in foods

Ledoux

Juanéda²,

Sébédio

2007

Euro J Lipid Sci & Tech

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Most of fatty acid double bonds are in cis configuration, but some processes may isomerise double bonds from cis to trans configuration and from their naturally occurring positions in the carbon chain. Since some fatty acids with trans double bond(s) are suspected to have adverse effects, several countries have regulated the inclusion of trans fatty acid (TFA) content labelling. The French governmental authorities requested AFSSA to propose recommendations regarding food labelling. This first article summarises the discussion on a regulatory TFA definition and reviews the occurrence and origins of TFA in foods. From a chemical point of view, a TFA is any kind of fatty acid that has one or more double bond(s) in trans configuration, but restricted TFA definitions have been proposed for food labelling purposes. These definitions exclude fatty acids with conjugated double bonds on different criteria which are commented on in this paper. Taking into account the goal of TFA labelling and the potential harmful properties of some trans conjugated fatty acids, the working group proposes the chemical definition for TFA labelling purposes. The main TFA natural origin is ruminal biohydrogenation, and therefore TFA are present in dairy products and ruminant meat. TFA are also found in domestically or industrially processed foods due to hydrogenation or heat treatment effects on oils and fats. Although the TFA molecules produced by both natural and industrial processes are often quite similar, TFA distribution profiles and levels are very different from one case to another.

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Section: Discussionmentioning

confidence: 99%

Trans fatty acids: Definition and occurrence in foods

Ledoux

Juanéda²,

Sébédio

2007

Euro J Lipid Sci & Tech

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“…Gas-liquid chromatography (GC) on highly polar columns such as 100m CPSil 88 or equivalent, as illustrated in Fig. 1, has been considered as a good compromise to determine the quantities of trans fatty acids in such food products (Sébédio and Ratnayake 2008;Juaneda et al 2007;Destaillats et al 2007). Under good chromatographic conditions, a group composed of Δ4t-to Δ11t-18:1 isomers appears to be quantifiable as a bulk.…”

Section: Analysis Of Trans Monounsaturated Fatty Acidsmentioning

confidence: 99%

“…The minor drawbacks outlined above can be avoided by using a pre-fractionation step using AgNO 3 -TLC (Sébédio (2008) and Juaneda et al (2007). The analysis of the margarine sample (top) was carried out on a CPSil 88 column isothermally at 180°C while the milk fat (bottom) was run on a CPSil column held at 60°C for 5 min the programmed to 165°C at 14°C/ min and programmed to 225°C at 2°C/min.…”

Section: Analysis Of Trans Monounsaturated Fatty Acidsmentioning

confidence: 99%

Analytical Methods for Quantification of Modified Fatty Acids and Sterols Formed as a Result of Processing

et al. 2008

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Fats and oils are often submitted to technological treatments before being consumed. Some treatments like refining, hydrogenation, and frying often lead to the formation of modified fatty acids such as cyclic fatty acid monomers (CFAM), geometrical fatty acid isomers, and/or oxidized fatty acids and sterols (cholesterol and phytosterols). Both cholesterol oxidation products (COP) and phytosterol oxidation products (POP), may be present in foods. As some of the newly formed components may present some adverse effects upon consumption, methods have been developed to analyze these compounds in food products and biological samples. Gas liquid chromatography (GC) on long polar columns (100m) is a good choice to quantify trans mono-and polyunsaturated fatty acids. In some cases a pre-fractionation step using silver nitrate thin layer chromatography (AgNO 3 -TLC) may be necessary to avoid GC overlapping of cis and trans isomers. Analysis of CFAM usually involves transformation of the sample in fatty acid methyl esters (FAME) which after addition of an internal standard (IS) are further hydrogenated. An enrichment step using reverse phase high performance liquid chromatography (RP-HPLC) permits to obtain a fraction which consists of a mixture of CFAM and the IS. This fraction is further analyzed by GC on a polar column. The analysis of oxidized triacylglycerol monomers (oxTG) as a group was feasible by a combination of adsorption and sizeexclusion chromatography. Quantification in used frying fats and oils around the limit of rejection for human consumption (25% polar compounds) has shown that the amount of oxTG range 5.9-9.4% expressed on fat or oil weight. In foods and biological tissues, the level of oxidized sterols (SOP) is often a very small fraction of their unoxidized forms. Analysis of SOP involved extraction of lipids, saponification or transesterification, enrichment, and subsequent qualitative and quantitative determination by GC and GC-MS, or HPLC and HPLC-MS. In addition, enrichment of SOP requires complete separation from the unoxidized sterols in order to separate these compounds even by high resolution GC capillary columns.

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“…Each of these methods exhibits advantages and drawbacks. GC can be accomplished with equipment available in many laboratories; it detects lower levels of TFA and allows for the quantification of individual fatty acids in the course of determining a full fatty acid profile (Phillips et al, 2010;Juanéda et al, 2007;Molkentin and Precht, 1995;Ratnayake and BeareRogers, 1990;Ledoux et al, 2000;huang et al, 2006;Aro et al, 1998;Delmonte and Rader, 2007;Tasan et al, 2011). Ratnayake et al, (2002) discussed the temperature sensitive resolution of cis/trans isomers of fatty acid isomers in PhF on 100 m SP2560 and CP-Sil88 capillary columns on GC, which eventually lead to the approval of AOCS Ce 1h-05 method for determination of cis/trans fatty acids vegetable or non-ruminant fats and oils (Ratnayake et al, 2006).…”

Section: Lod and Loqmentioning

confidence: 99%

Separation of cis/trans fatty acid isomers on gas chromatography compared to the Ag-TLC method

Kiran¹,

Reshma²,

Sundaresan³

2013

Grasas y Aceites

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RESUMENSeparación de isómeros cis/trans de ácidos grasos mediante cromatografía de gases, comparación con el método Ag-TLC.El presente estudio investiga la separación de isómeros cis/trans de ácidos grasos mediante cromatografía de gases (GC) utilizando una columna de SP2560 de 75 m y diferentes condiciones que incluyen un programa isotérmico y una programación temperatura-tiempo. La programación temperatura-tiempo mostró una mejor separación de isómeros cis / trans de los ácidos grasos C 14:1 , C 16:1 , C 18:1 , C 18:2 y C 18:3 con los ácidos grasos de cadena corta en comparación con el programa isotermo. La separación de los isómeros trans/trans de los ácidos grasos C 18:1 incluyendo ácido elaídico (C 18:1 Δ9t) y ácido vaccénico (C 18:1 Δ11t) fué difícil mediante programación temperatura-tiempo. La cromatografía en capa fina impregnada con nitrato de plata (Ag-TLC) se realizó para separar fracciones cis/trans y el análisis de la fracciones se llevó a cabo mediante GC. El análisis GC mostró co-elución de los isómeros trans del ácido graso C 18:1 . Así, el estudio muestra que una programación temperatura-tiempo en GC con columna de cianopropilo altamente polar es suficiente para resolver los ácidos grasos trans, junto con los ácidos grasos de cadena corta cuando un gran número de muestras tiene que ser analizado. PALABRAS CLAVE: Ácidos grasos trans -Cromatografía de gases -Fraccionamiento Ag-TLC -Resolución SUMMARY Separation of cis/trans fatty acids isomers on gas chromatography compared to the Ag-TLC methodThe present study investigates the separation of the cis/ trans isomers of fatty acids on the 75 m SP2560 column under different gas chromatographic (GC) conditions including an isothermal program and a time-temperature program. The time-temperature program showed improved separation of cis/trans isomers of C 14:1 , C 16:1 , C 18:1 , C 18:2 and C 18:3 fatty acids along with short chain fatty acids compared to the isothermal program. The separation of trans/trans isomers of C 18:1 fatty acids including elaidic acid (C 18:1 Δ9t) and vaccenic acid (C 18:1 Δ11t) was difficult with the time-temperature program. The thin layer chromatography impregnated with silver nitrate (Ag-TLC) method was performed to separate cis/trans fractions and GC analysis was carried out with the trans fraction. But GC analysis showed a co-elution of trans isomers of C 18:1 fatty acid. Thus the study shows that a time-temperature programmed GC method with the highly polar cyanopropyl column is sufficient to resolve trans fatty acids along with short chain fatty acids when a large number of samples has to be analyzed.

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Analytical methods for determination of trans fatty acid content in food

Cited by 41 publications

References 80 publications

Trans fatty acids: Definition and occurrence in foods

Trans fatty acids: Definition and occurrence in foods

Analytical Methods for Quantification of Modified Fatty Acids and Sterols Formed as a Result of Processing

Separation of <i>cis/trans</i> fatty acid isomers on gas chromatography compared to the Ag-TLC method

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